足外侧柱延长术矫正严重可复性平足畸形的生物力学研究

Adult-acquired flatfoot is a common foot deformity. Surgical intervention for the flexible flatfoot deformity (stage Ⅱ) is very necessary and lateral column lengthening with Evans procedure is often applied for the severe flexible deformity (stage ⅡB). However the complications after this procedure, such as calcaneocuboid joint degeneration and lateral forefoot pain, cannot be ignored. Most of the previous studies just focused on the biomechanical changes after lateral column lengthening, and the osteotomy line of Evans procedure is always set at 1cm proximal to the calcaneocuboid joint for all of the patients. The impact of different degrees of the lengthening is ignored and the individual design of the osteotomy for the patients with various foot length is necessary. In this study, the osteotomy line is designed based on the anatomical measurement, and the results are standardized by the calcaneus length. Furthermore, the changes of the flatfoot biomechanical environment after sequential lengthening of the lateral column is recorded dynamically on both the three dimensional finite element and the cadaver model. The technique of real-time X-ray measurement, the joint pressure survey and the plantar pressure analysis were applied in this study, to explore the relationship between over lengthening of the lateral column and the complications after Evans procedure. The purpose of this study is to standardize the lateral column lengthening procedure, reduce the complication rate and improve the operative effect.

成人获得性平足是足踝外科的常见病，足外侧柱延长术（Evans手术）是用于严重可复性平足（ⅡB期）矫形的一种常用术式。但在取得良好矫形效果的同时，此术式也会带来跟骰关节退变、前中足外侧足底疼痛等并发症。既往研究大多停留在观察外侧柱延长后足部生物力学指标的变化，而跟骨截骨的位置也都经验性的设定在跟骰关节后1cm。忽视了延长程度本身对足生物力学环境的影响，且对不同足长的患者缺少跟骨截骨位置的个性化设计。本研究通过解剖学测量，找出损伤最小的截骨位置，并采用跟骨长度对截骨位置进行标化；通过三维有限元和实体生物力学研究，采用实时X线测量、电阻压敏片和足底压力分析等技术，对不同程度外侧柱延长后足部生物力学环境的改变进行动态观测，并找出过度延长与外侧柱延长术后并发症的相互关系。为临床上规范开展外侧柱延长术、降低术后并发症发生率、提高手术疗效提供理论依据。